"Right now, we have a situation where Lyft is spending very aggressively to gain [market] share," he said. Khosrowshahi said he didn't think Uber could be "particularly profitable" in the U.S. for at least the next six months.

Uber has been bolstering its finances, in part to better compete with Lyft. On Sunday, Uber said it had struck a deal potentially worth as much as $10 billion in which an investor group — led by Japanese telecommunications giant SoftBank and San Francisco investment firm Dragoneer — could buy a stake in Uber.

The investor group plans to buy about $1 billion of newly issued shares and make a tender offer for about 14% of Uber's existing shares, according to a person with knowledge of the deal who was not authorized to discuss it publicly.

Times staff writers Tracey Lien and Lauren Raab contributed to this report.

UPDATES:

9:10 a.m.: This article was updated with comments from Uber Chief Executive Dara Khosrowshahi and with information about Uber's deal with an investor group led partly by SoftBank.